Grinding-mill



W. N.GOSGROV E. Grinding Mill. No. 242,756. Patented June 1-4, 188].

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Grinding Mill.

No. 242,756. J Patente dj'une 14, I881.

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1 UNITED STATES PATENT OFFICE.

WILLIAM N. COSGROVE, OF FARIBAULT, MINNESOTA.

GRlNDIliG-MILL.

SPECIFICATION forming part of Lettersilatent No. 242,756, dated June 14, 1881.

Application filed liebruary 12 1880.

To all whom it may concern:

Be it known that I, WILLIAM N. Coscnovn,

of Faribault, in the county of Rice and State of Minnesota, have invented certain new and useful Improvements in Grinding-Mills; and I do hereby declare the following to be a full, clear, and exactdescription of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is an end view of the mill; Fig. 2, a vertical section taken on the line mar, Fig. 3; and Figs. 3 and 4, side and top views, respect ively, with part of the casing thrown open.

Similar letters of reference in the several figures denote the same parts.

This invention relates to certain novel improvements in vertical grinding-mills, which will behereinafter fully described, and pointed out in the claims.

In the drawings, A represents the casing of the mill, B the large grinding-roll, and O G C O the small grinding-rolls, arranged around the periphery of the roll 13. The small rolls are located at sufficient distances apart to accommodate screen-sections l) D D of wire or bolting cloth, between them, as shown in The journals of the small rolls are mounted in boxes or bearings that are capable of beingindependently adj ustedback and forth in radial guides a a by means of screw-rods f and hand-wheels h. This arrangement enables the small rolls to beindependently adjusted nearer to or farther from the large roll B at pleasure. The journals of the large roll are also mounted in movable bearings or boxes, and by means of screw-rodst' and hand-wheels ]i) can be adjusted with respect to. the small rolls. The small rolls and the large roll rotate toward each other, and motion is preferably imparted to them by means of a large pulley, F, on one end of thejourn'al of the large roll, driven from any prime mover, a second pulley,

G, on the other end of the journal of said large roll, pulleys H H H H on the journals of the small rolls, an idle-pulley, T, and a connectingbelt, I, applied as shown in Fig. 1.

In order that the material passed between the small rolls and the large roll may be subjected to a grinding or rubbing action, instead of being nearly crushed, the said rolls are so proportioned and geared that their peripheries travel at different rates of speed.

I M cated air-trunks N N N .&c., connected by air-tubes n a n to a common tube, 0, A suctionfan or other means for producing a suc- 1 tion is applied to the outer end of the tube 0, and strong currents are thereby induced inthe The screen -sections D D l) are held in frame K K" K secured to the sides of the casing, and below each screen-section and over the top of the rolls 0 C O are placed guard plates L L L upon which the flour and middlings screened out through the screens fall, and are conducted into the chambers M M M Within the chambers M M M M are lochambers M M M M causing a draft through the screens sufficient to draw off the fine flour or middlings as fast as made. That the flour I and middlin gs thus passed through the screens may not be carried off through the air-trunks by. the suction, said air -trunks are covered with cloth or some other fibrous material which will admit of the passage of air but not permit a ny flour to go through. The flour and middlings pass out of the compartments through openings R in the outer casin g, and are thence conveyed to the proper bolts and purifiers. If desired, the flour and middlings from each screen may be kept apart from the rest and conveyed to difl'erent bolts and purifiers and separately treated.

Both the large grinding-rollB and the small grinding-rolls O G G G are provided on their peripheries with grooves h, arranged spirally after the manner of screw-threads, each groove extending around several times. The grooves h on the large roll B have a shearing action from right to left, while the grooves on the cooperating small rolls 0 G O 0 have preferablya shearing action from left to right, the tendency of one set of grooves being to carry the material being ground in one direction, and the tendency of the other set being to carry it in the opposite direction. Each roll is also further provided with other grooves, g, runnin g parallel, or nearly so, with its axis of rota tion, the operation of said grooves being to subject the material to ashearing action transversely of the rolls in addition to the oblique shearing action of the spiral grooves 71, thus rendering the rolls doubly effective.

The operation of the mill is as follows: The grain, being fed from the hopper, is subjected to the action of the first small roll, 0, and the too large roll B, and the resulting fine flour and middlings are as fast as made drawn off through the screen D by the suction produced, as before described. The remaining material then passes between the second roll, 0, and the roll B, which are adjusted slightly nearer together, when it is further reduced and the resulting fine flour and middlings carried out through the screen-section D, and so on throughout the mill, the material being subjected to alternate reductions and screenings until all the flour and middlingshavebeeneliminated. Thefiourand middlings screened out passinto the chambers behind the screens, and thence out of the mill, after which they are conveyed to the proper bolts or purifiers, as before described.

I claim as my invention 1. In a grinding-mill, the combination of a large grinding cylinder or roll, a series of small grinding-rolls arranged around the grindingperipheryof thelargeroll and adapted to be adjusted nearer to orfarther from the same, whereby to gradually reduce the material toa greater degrrc of fineness, and screens or screen-sections between the small rolls for screening out the fine flourand middlin gs resultingfrom each reduction, substantially as described.

2. Ina grinding-mill, the combination of a large grinding cylinder or roll, aseries of small grinding-rolls arranged around the grindingperiphery of the large roll and adapted to be adjusted nearer to or farther from the same, whereby to gradually reduce the material to a greater degree of fineness, screens or screensections between the small rolls for screening 5 out the fine flour and middlings, and asuction or suctions behind the screen-sections for assisting in screening out the fineflourand middlings as fast as made, substantially as described.

3. In a grinding-mill,thecombination of the large grinding cylinder or roll, the series of small rolls, the screen-sections between the smallrolls, the chambersMM M M provided with the air-trunks N N N covered with cloth or other fibrous material, and an exhaust applied to the said air-truuks, substantially as described, for the purpose specified.

4. Thecombination, with thelarge grinding cylinder or roll, the series of small grindingrolls co-operating therewith, and the screens between the small rolls, of the chambers M MW M M, arranged behind the screens and containing the cloth-covered air-trunks, and having openings for the escape of the fiour and middlings, substantially as described.

5. In a grinding-milLa grinding-rollhaving peripheral grooves running substantially parallel to its axis of rotation, and also having other grooves running spirally around it, in combination with a co-operating roll similarly grooved, but adapted to revolve in an opposite direction, substantially as described, for the purpose specified.

WILLIAM N. OOSGROVE.

Witnesses:

J OSEPH O. MOLD, J. H. HARDING. 

